U.S. patent application number 14/207847 was filed with the patent office on 2014-09-18 for led lamp.
This patent application is currently assigned to Cree, Inc.. The applicant listed for this patent is Cree, Inc.. Invention is credited to Nicholas Desilva, Robert Higley, Shawn Keeney, Michael Leung, Dante Nava, Charles Richards, Mark Youmans.
Application Number | 20140268772 14/207847 |
Document ID | / |
Family ID | 51526307 |
Filed Date | 2014-09-18 |
United States Patent
Application |
20140268772 |
Kind Code |
A1 |
Richards; Charles ; et
al. |
September 18, 2014 |
LED LAMP
Abstract
A LED lamp has a base and an at least partially optically
transmissive enclosure connected to the base. A heat sink is
partially disposed in the enclosure and supports a plurality of
LEDs. The heat sink comprising a mounting portion positioned in the
enclosure for supporting the LEDs and a heat dissipating portion
exposed to the ambient environment where the interior of the
enclosure is exposed to the ambient environment. The heat sink have
a plurality of separate heat sink structures that are mounted to
the lamp independently of one another. Each heat sink structure may
have a thickness of approximately 1-5 mm. Each heat sink structure
may in some embodiments weigh approximately 3.8 to 7.7 grams and in
other embodiments weigh approximately 27 grams.
Inventors: |
Richards; Charles; (Cary,
NC) ; Keeney; Shawn; (Chapel Hill, NC) ;
Youmans; Mark; (Goleta, CA) ; Leung; Michael;
(Ventura, CA) ; Desilva; Nicholas; (Four Oaks,
NC) ; Nava; Dante; (Cary, NC) ; Higley;
Robert; (Cary, NC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Cree, Inc. |
Durham |
NC |
US |
|
|
Assignee: |
Cree, Inc.
Durham
NC
|
Family ID: |
51526307 |
Appl. No.: |
14/207847 |
Filed: |
March 13, 2014 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
61778971 |
Mar 13, 2013 |
|
|
|
Current U.S.
Class: |
362/249.02 |
Current CPC
Class: |
F21Y 2107/00 20160801;
F21Y 2115/10 20160801; F21V 29/506 20150115; F21K 9/232 20160801;
F21V 29/83 20150115; F21V 29/70 20150115; F21V 3/00 20130101 |
Class at
Publication: |
362/249.02 |
International
Class: |
F21K 99/00 20060101
F21K099/00; F21V 29/00 20060101 F21V029/00 |
Claims
1. A LED lamp comprising: a base; an at least partially optically
transmissive enclosure connected to the base; a heat sink partially
disposed in the enclosure and supporting a plurality of LEDs
operable to emit light when energized, the heat sink comprising a
mounting portion positioned in the enclosure for supporting the
LEDs and a heat dissipating portion exposed to the ambient
environment where the interior of the enclosure is exposed to the
ambient environment.
2. The lamp of claim 1 wherein the lamp has a lumen output of
approximately at least 1600 lumens in a steady state operation.
3. The lamp of claim 1 wherein the lamp has a color rendering index
of approximately at least 80 with a correlated color temperature
(CCT) of less than approximately 3000.
4. The lamp of claim 1 wherein the lamp has an efficiency of at
least approximately 80 lumens per Watt (LPW).
5. The lamp of claim 1 wherein the base comprises an Edison
base.
6. The lamp of claim 1 wherein the plurality of LEDs are mounted on
at least one thermally conductive submount.
7. The lamp of claim 6 wherein the at least one submount is
arranged such that the plurality of LEDs surround a longitudinal
axis of the lamp and emit light generally toward the enclosure.
8. The lamp of claim 6 wherein the at least one submount comprises
at least one of a PCB, metal core printed circuit board, FR4 board,
lead frame or flex circuit.
9. The lamp of claim 6 wherein the at least one submount is bent
into a three-dimensional shape.
10. The lamp of claim 6 wherein the at least one submount is
approximately 20 square mm.
11. The lamp of claim 1 the lamp has a total power of approximately
21 Watts and the junction temperature of the plurality of LEDs is
between approximately 105 and 111.degree. C.
12. The lamp of claim 1 wherein lamp electronics are in the
electrical path and are contained in a housing comprising a first
portion that is connected to the base and a second portion that
extends into the heat sink.
13. The lamp of claim 1 comprising openings that communicate the
interior of the enclosure with the exterior of the lamp.
14. The lamp of claim 13 wherein the openings are formed in a frame
that connects the enclosure to the base.
15. The lamp of claim 1 wherein the heat sink comprises a plurality
of separate heat sink structures that are mounted to the lamp
independently of one another.
16. The lamp of claim 15 wherein each of the plurality of heat sink
structures support at least one LED.
17. The lamp of claim 15 wherein passages are formed adjacent the
plurality of heat sink structures that allow air to circulate from
the ambient environment around the heat sink.
18. The lamp of claim 15 wherein each of the plurality of heat sink
structures comprises one or more mounting surfaces for mounting a
submount that supports the plurality of LEDs such that the submount
is thermally coupled to the heat sink.
19. The lamp of claim 18 wherein the mounting surfaces are disposed
on the heat sink at an angle other than 90 degrees relative to the
longitudinal axis of the lamp.
20. The lamp of claim 15 wherein each of the plurality of heat sink
structures comprise a fin structure that is exposed to the exterior
of the lamp.
21. The lamp of claim 15 wherein each of the plurality of heat sink
structures have a thickness of approximately 3-5 mm.
22. The lamp of claim 15 wherein each of the plurality of heat sink
structures weighs between approximately 20 and 35 grams.
23. The lamp of claim 1 wherein the heat sink has a total weight of
approximately 110 to 170 grams.
24. The lamp of claim 15 wherein each of the plurality of heat sink
structures have a thickness of approximately 1 to 3 mm.
25. The lamp of claim 15 wherein each of the plurality of heat sink
structures weigh approximately 3.8 to 10.0 grams.
26. The lamp of claim 1 wherein the heat sink has a total weight of
approximately 15 to 50 grams.
27. A LED lamp comprising: a base; an at least partially optically
transmissive enclosure connected to the base; a heat sink partially
disposed in the enclosure and supporting a plurality of LEDs
operable to emit light when energized, the heat sink comprising an
interior space and a mounting portion positioned in the enclosure
for supporting the LEDs and a heat dissipating portion exposed to
the ambient environment where the mounting portion and the interior
space are exposed to the ambient environment.
28. A LED lamp comprising: a base; an at least partially optically
transmissive enclosure having an interior and connected to the
base; a heat sink partially disposed in the enclosure and
supporting a plurality of LEDs operable to emit light when
energized, the heat sink comprising an interior space and a
mounting portion positioned in the enclosure for supporting the
LEDs, the interior space communicating the interior of the
enclosure to the ambient environment.
29. A LED lamp comprising: a base; an at least partially optically
transmissive enclosure connected to the base; a heat sink partially
disposed in the enclosure and supporting a plurality of LEDs
operable to emit light when energized, a portion of the heat sink
being positioned between the enclosure and the base where a portion
of the heat sink is exposed to an exterior of the lamp, the portion
of the heat sink comprising openings.
Description
[0001] This application claims benefit of priority under 35 U.S.C.
.sctn.119(e) to the filing date of U.S. Provisional Application No.
61/778,971, as filed on Mar. 13, 2013, which is incorporated herein
by reference in its entirety.
BACKGROUND
[0002] Light emitting diode (LED) lighting systems are becoming
more prevalent as replacements for older lighting systems. LED
systems are an example of solid state lighting (SSL) and have
advantages over traditional lighting solutions such as incandescent
and fluorescent lighting because they use less energy, are more
durable, operate longer, can be combined in multi-color arrays that
can be controlled to deliver virtually any color light, and
generally contain no lead or mercury. A solid-state lighting system
may take the form of a lighting unit, light fixture, light bulb, or
a "lamp."
[0003] An LED lighting system may include, for example, a packaged
light emitting device including one or more light emitting diodes
(LEDs), which may include inorganic LEDs, which may include
semiconductor layers forming p-n junctions and/or organic LEDs,
which may include organic light emission layers. Light perceived as
white or near-white may be generated by a combination of red,
green, and blue ("RGB") LEDs. Output color of such a device may be
altered by separately adjusting supply of current to the red,
green, and blue LEDs. Another method for generating white or
near-white light is by using a lumiphor such as a phosphor. Still
another approach for producing white light is to stimulate
phosphors or dyes of multiple colors with an LED source. Many other
approaches can be taken.
[0004] An LED lamp may be made with a form factor that allows it to
replace a standard incandescent bulb, or any of various types of
fluorescent lamps. LED lamps often include some type of optical
element or elements to allow for localized mixing of colors,
collimate light, or provide a particular light pattern. Sometimes
the optical element also serves as an envelope or enclosure for the
electronics and or the LEDs in the lamp.
[0005] Since, ideally, an LED lamp designed as a replacement for a
traditional incandescent or fluorescent light source needs to be
self-contained; a power supply is included in the lamp structure
along with the LEDs or LED packages and the optical components. A
heatsink is also often needed to cool the LEDs and/or power supply
in order to maintain appropriate operating temperature.
SUMMARY OF THE INVENTION
[0006] In one embodiment a LED lamp comprises a base and an at
least partially optically transmissive enclosure connected to the
base. A heat sink is partially disposed in the enclosure and
supports a plurality of LEDs operable to emit light when energized.
The heat sink comprising a mounting portion positioned in the
enclosure for supporting the LEDs and a heat dissipating portion
exposed to the ambient environment where the interior of the
enclosure is exposed to the ambient environment.
[0007] The lamp may have a lumen output of approximately at least
1600 lumens in a steady state operation. The lamp may have a color
rendering index of approximately at least 80 with a correlated
color temperature (CCT) of less than approximately 3000. The lamp
may have an efficiency of at least approximately 80 lumens per Watt
(LPW). The base may comprise an Edison base. The LEDs may be
mounted on a thermally conductive submount. The LEDs may surround a
longitudinal axis of the lamp and may emit light generally toward
the enclosure. The submount may comprise at least one of a PCB,
metal core printed circuit board, FR4 board, lead frame or flex
circuit. The submount may be folded into a three-dimensional shape.
The at least one submount may have a thickness of about 0.25 mm-2.0
mm thick. The submounts may have a surface area of approximately 20
square mm. The lamp may have a total power of approximately 21
Watts and the junction temperature of the plurality of LEDs may be
between approximately 105 and 111.degree. C. Lamp electronics in
the electrical path may be contained in a housing comprising a
first portion that is connected to the base and a second portion
that extends into the heat sink. The enclosure may comprise a first
portion comprising an optically tranmissive material and a second
portion comprising openings that communicate the interior of the
enclosure with the exterior of the lamp. The heat sink may comprise
a plurality of separate heat sink structures that are mounted to
the lamp independently of one another. Each heat sink structure may
support at least one LED. Passages may be formed between and behind
the adjacent heat sink structures that allow air to circulate from
the ambient environment around the heat sink. Each heat sink
structure may comprise one or more mounting surfaces for mounting
the submounts such that the submounts are thermally coupled to the
heat sink. The heat sink structures may comprise a fin structure
that is located in the openings. The mounting surfaces may be
disposed on the heat sink at an angle other than 90 degrees
relative to the longitudinal axis of the lamp. Each of the
plurality of heat sink structures may comprise a fin structure that
is exposed to the exterior of the lamp. Each of the plurality of
heat sink structures may have a thickness of approximately 3-5 mm.
Each of the plurality of heat sink structures may weigh between
approximately 20 and 35 grams. The heat sink may have a total
weight of approximately 110 to 170 grams. Each of the plurality of
heat sink structures may have a thickness of approximately 1 to 3
mm. Each of the plurality of heat sink structures may weigh
approximately 3.8 to 10.0 grams. The heat sink may have a total
weight of approximately 15 to 50 grams.
[0008] In some embodiments a LED lamp comprises a base and an at
least partially optically transmissive enclosure connected to the
base. A heat sink is partially disposed in the enclosure and
supports a plurality of LEDs operable to emit light when energized.
The heat sink comprises an interior space and a mounting portion
positioned in the enclosure for supporting the LEDs and a heat
dissipating portion exposed to the ambient environment where the
mounting portion and the interior space are exposed to the ambient
environment.
[0009] In some embodiments, a LED lamp comprises a base and an at
least partially optically transmissive enclosure having an interior
and connected to the base. A heat sink is partially disposed in the
enclosure and supports a plurality of LEDs operable to emit light
when energized. The heat sink comprises an interior space and a
mounting portion positioned in the enclosure for supporting the
LEDs where the interior space communicates the interior of the
enclosure to the ambient environment.
[0010] In some embodiments a LED lamp comprises a base and an at
least partially optically transmissive enclosure connected to the
base. A heat sink is partially disposed in the enclosure and
supports a plurality of LEDs operable to emit light when energized.
A portion of the heat sink is positioned between the enclosure and
the base where a portion of the heat sink is exposed to an exterior
of the lamp where the portion of the heat sink comprises
openings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a perspective view of an embodiment of the lamp of
the invention.
[0012] FIG. 2 is a perspective view of an embodiment of a portion
of a heat sink used in the lamp of FIG. 1.
[0013] FIG. 3 is a top view of the lamp of FIG. 1.
[0014] FIG. 4 is an exploded view of the lamp of FIG. 1.
[0015] FIG. 5 is a plan view of an embodiment of a submount used in
the lamp of FIG. 1.
[0016] FIG. 6 is an embodiment of a housing used in the lamp of
FIG. 1.
[0017] FIG. 7 is a perspective view of another embodiment of the
lamp of the invention.
[0018] FIG. 8 is a perspective view of an embodiment of a portion
of a heat sink used in the lamp of FIG. 7.
[0019] FIG. 9 is a perspective view of another embodiment of the
lamp of the invention.
[0020] FIG. 10 is a perspective view of an embodiment of a portion
of a heat sink used in the lamp of FIG. 9.
[0021] FIG. 11 is a perspective view of an embodiment of a bendable
submount and LEDs usable in various embodiments of the lamp of the
invention.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0022] Embodiments of the present invention now will be described
more fully hereinafter with reference to the accompanying drawings,
in which embodiments of the invention are shown. This invention
may, however, be embodied in many different forms and should not be
construed as limited to the embodiments set forth herein. Rather,
these embodiments are provided so that this disclosure will be
thorough and complete, and will fully convey the scope of the
invention to those skilled in the art. Like numbers refer to like
elements throughout.
[0023] It will be understood that, although the terms first,
second, etc. may be used herein to describe various elements, these
elements should not be limited by these terms. These terms are only
used to distinguish one element from another. For example, a first
element could be termed a second element, and, similarly, a second
element could be termed a first element, without departing from the
scope of the present invention. As used herein, the term "and/or"
includes any and all combinations of one or more of the associated
listed items.
[0024] It will be understood that when an element such as a layer,
region or submount is referred to as being "on" or extending "onto"
another element, it can be directly on or extend directly onto the
other element or intervening elements may also be present. In
contrast, when an element is referred to as being "directly on" or
extending "directly onto" another element, there are no intervening
elements present. It will also be understood that when an element
is referred to as being "connected" or "coupled" to another
element, it can be directly connected or coupled to the other
element or intervening elements may be present. In contrast, when
an element is referred to as being "directly connected" or
"directly coupled" to another element, there are no intervening
elements present.
[0025] Relative terms such as "below" or "above" or "upper" or
"lower" or "horizontal" or "vertical" or "top" or "bottom" may be
used herein to describe a relationship of one element, layer or
region to another element, layer or region as illustrated in the
figures. It will be understood that these terms are intended to
encompass different orientations of the device in addition to the
orientation depicted in the figures.
[0026] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the invention. As used herein, the singular forms "a", "an" and
"the" are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood
that the terms "comprises" "comprising," "includes" and/or
"including" when used herein, specify the presence of stated
features, integers, steps, operations, elements, and/or components,
but do not preclude the presence or addition of one or more other
features, integers, steps, operations, elements, components, and/or
groups thereof.
[0027] Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which this
invention belongs. It will be further understood that terms used
herein should be interpreted as having a meaning that is consistent
with their meaning in the context of this specification and the
relevant art and will not be interpreted in an idealized or overly
formal sense unless expressly so defined herein.
[0028] Unless otherwise expressly stated, comparative, quantitative
terms such as "less" and "greater", are intended to encompass the
concept of equality. As an example, "less" can mean not only "less"
in the strictest mathematical sense, but also, "less than or equal
to."
[0029] The terms "LED" and "LED device" as used herein may refer to
any solid-state light emitter. The terms "solid state light
emitter" or "solid state emitter" may include a light emitting
diode, laser diode, organic light emitting diode, and/or other
semiconductor device which includes one or more semiconductor
layers, which may include silicon, silicon carbide, gallium nitride
and/or other semiconductor materials, a submount which may include
sapphire, silicon, silicon carbide and/or other microelectronic
submounts, and one or more contact layers which may include metal
and/or other conductive materials. A solid-state lighting device
produces light (ultraviolet, visible, or infrared) by exciting
electrons across the band gap between a conduction band and a
valence band of a semiconductor active (light-emitting) layer, with
the electron transition generating light at a wavelength that
depends on the band gap. Thus, the color (wavelength) of the light
emitted by a solid-state emitter depends on the materials of the
active layers thereof. In various embodiments, solid-state light
emitters may have peak wavelengths in the visible range and/or be
used in combination with lumiphoric materials having peak
wavelengths in the visible range. Multiple solid state light
emitters and/or multiple lumiphoric materials (i.e., in combination
with at least one solid state light emitter) may be used in a
single device, such as to produce light perceived as white or near
white in character. In certain embodiments, the aggregated output
of multiple solid-state light emitters and/or lumiphoric materials
may generate warm white light output having a color temperature
range of from about 2200K to about 6000K.
[0030] Solid state light emitters may be used individually or in
combination with one or more lumiphoric materials (e.g., phosphors,
scintillators, lumiphoric inks) and/or optical elements to generate
light at a peak wavelength, or of at least one desired perceived
color (including combinations of colors that may be perceived as
white). Inclusion of lumiphoric (also called `luminescent`)
materials in lighting devices as described herein may be
accomplished by direct coating on solid state light emitter, adding
such materials to encapsulants, adding such materials to lenses, by
embedding or dispersing such materials within lumiphor support
elements, and/or coating such materials on lumiphor support
elements. Other materials, such as light scattering elements (e.g.,
particles) and/or index matching materials may be associated with a
lumiphor, a lumiphor binding medium, or a lumiphor support element
that may be spatially segregated from a solid state emitter.
[0031] Embodiments of the present invention provide a solid-state
lamp with centralized light emitters, more specifically, LEDs.
Multiple LEDs can be used together, forming an LED array. The LEDs
can be mounted on or fixed within the lamp in various ways. In at
least some example embodiments, a submount is used. The LEDs are
disposed at or near the central portion of the structural envelope
of the lamp. Since the LED array may be configured in some
embodiments to reside centrally within the structural envelope of
the lamp, a lamp can be constructed so that the light pattern is
not adversely affected by the presence of a heat sink and/or
mounting hardware, or by having to locate the LEDs close to the
base of the lamp. It should also be noted that the term "lamp" is
meant to encompass not only a solid-state replacement for a
traditional incandescent bulb as illustrated herein, but also
replacements for fluorescent bulbs, replacements for complete
fixtures, and any type of light fixture that may be custom designed
as a solid state fixture.
[0032] The figures show a lamp, 100, according to some embodiments
of the present invention. Lamp 100 may be used as an A-series lamp
with an Edison base 102, more particularly; lamp 100 is designed to
serve as a solid-state replacement for an A19 incandescent bulb.
While the lamp is disclosed as a replacement for an A19 bulb the
lamp may be made equivalent to other standard bulbs such as A21,
A23 or PAR standard bulbs, such as a replacement for a PAR-38, or
BR standard bulbs or other standard or non-standard sizes. In some
embodiments the lamp is an equivalent to a 100 watt incandescent
bulb. While the lamp is disclosed as equivalent to a 100 Watt
incandescent bulb the lamp may be made equivalent to other standard
incandescent bulbs such as 40 watt, 60 watt or the like or the lamp
may have a light out put that is different from standard
incandescent bulbs. The lamp 100 is an omnidirectional lamp.
[0033] The Edison base 102 as shown and described herein may be
implemented through the use of an Edison connector 103 and a form
or housing 105. The lamp 100 comprises a solid-state lamp
comprising multiple LEDs 127 used together, forming an LED array
130. The LEDs 127 can be mounted on or fixed within the lamp in
various ways. The LEDs 127 in the LED array 130 may comprise an LED
die disposed in an encapsulant such as silicone, and LEDs which are
encapsulated with a phosphor to provide local wavelength
conversion, as will be described later when various options for
creating white light are discussed. A wide variety of LEDs and
combinations of LEDs may be used including those described herein.
The LEDs 127 of the LED array 130 are mounted on submounts 129 and
are operable to emit light when energized through an electrical
connection. In the present invention the term "submount" is used to
refer to the support structure that supports the individual LEDs or
LED packages 127 and in one embodiment comprises a printed circuit
board or "PCB" although it may comprise other structures. In some
embodiments, a driver and/or power supply may be included with the
LED's on the submounts and may be formed by components on the
submount.
[0034] Enclosure 112 is, in some embodiments, made of glass,
quartz, borosilicate, silicate, polycarbonate, other plastic or
other suitable material. The enclosure 112 may be at least
partially transmissive and may be entirely optically transmissive
such that light may be emitted from the lamp through the enclosure.
The enclosure may be of similar shape to that commonly used in
traditional incandescent bulbs. In some embodiments, the enclosure
112 is coated on the inside with silica, providing a diffuse
scattering layer that produces a more uniform far field pattern.
The enclosure may also be etched, frosted or coated. The diffuser
may also be provided by the optical characteristics of the material
of the enclosure itself such as where the enclosure is made of
polycarbonate. Alternatively, the surface treatment may be omitted
and a clear enclosure may be provided. The enclosure 112 may also
be provided with a shatter proof or shatter resistant coating. In
the illustrated embodiment the enclosure 112 is clear in order to
show the internal components of the lamp. In use the enclosure 112
may comprise a diffuser such that the internal components may not
be visible or may be only partially visible. It should also be
noted that in this or any of the embodiments shown here, the
optically transmissive enclosure or a portion of the optically
transmissive enclosure could be coated or impregnated with
phosphor.
[0035] A lamp base 102 such as an Edison base comprising an Edison
screw 103 functions as the electrical connector to connect the lamp
100 to an electrical socket or other connector. Depending on the
embodiment, other base configurations are possible to make the
electrical connection such as other standard bases or
non-traditional bases. Base 102 may retain, or partially retain,
the electronics 110 for powering lamp 100 and may include a power
supply and/or driver and form all or a portion of the electrical
path between the mains and the LEDs. Base 102 may also include only
part of the power supply circuitry while some smaller components
reside on the submounts 129. The LEDs 127 of the LED array are
operable to emit light when energized through an electrical
connection. With the embodiment of FIG. 1, as with many other
embodiments of the invention, the term "electrical path" can be
used to refer to the entire electrical path to the LEDs 127,
including an intervening power supply disposed between the
electrical connection that would otherwise provide power directly
to the LEDs and the LED array, or it may be used to refer to the
connection between the mains and all the electronics in the lamp,
including the power supply. The term may also be used to refer to
the connection between the power supply and the LED array.
Conductors 133 may be used to electrically connect the lamp
electronics 110 to the LEDs 127 or electrically conductive
substrates 129. The conductors 133 may comprise wires, ribbons,
copper traces, conductive elements and/or other components.
[0036] In one example embodiment, the inductors and capacitor that
form part of the EMI filter are in the Edison base. Suitable power
supplies and drivers are described in U.S. patent application Ser.
No. 13/462,388 filed on May 2, 2012 and titled "Driver Circuits for
Dimmable Solid State Lighting Apparatus" which is incorporated
herein by reference in its entirety; U.S. patent application Ser.
No. 12/775,842 filed on May 7, 2010 and titled "AC Driven Solid
State Lighting Apparatus with LED String Including Switched
Segments" which is incorporated herein by reference in its
entirety; U.S. patent application Ser. No. 13/192,755 filed Jul.
28, 2011 titled "Solid State Lighting Apparatus and Methods of
Using Integrated Driver Circuitry" which is incorporated herein by
reference in its entirety; U.S. patent application Ser. No.
13/339,974 filed Dec. 29, 2011 titled "Solid-State Lighting
Apparatus and Methods Using Parallel-Connected Segment Bypass
Circuits" which is incorporated herein by reference in its
entirety; U.S. patent application Ser. No. 13/235,103 filed Sep.
16, 2011 titled "Solid-State Lighting Apparatus and Methods Using
Energy Storage" which is incorporated herein by reference in its
entirety; U.S. patent application Ser. No. 13/360,145 filed Jan.
27, 2012 titled "Solid State Lighting Apparatus and Methods of
Forming" which is incorporated herein by reference in its entirety;
U.S. patent application Ser. No. 13/338,095 filed Dec. 27, 2011
titled "Solid-State Lighting Apparatus Including an Energy Storage
Module for Applying Power to a Light Source Element During Low
Power Intervals and Methods of Operating the Same" which is
incorporated herein by reference in its entirety; U.S. patent
application Ser. No. 13/338,076 filed Dec. 27, 2011 titled
"Solid-State Lighting Apparatus Including Current Diversion
Controlled by Lighting Device Bias States and Current Limiting
Using a Passive Electrical Component" which is incorporated herein
by reference in its entirety; and U.S. patent application Ser. No.
13/405,891 filed Feb. 27, 2012 titled "Solid-State Lighting
Apparatus and Methods Using Energy Storage" which is incorporated
herein by reference in its entirety.
[0037] The AC to DC conversion may be provided by a boost topology
to minimize losses and therefore maximize conversion efficiency.
The boost supply is connected to high voltage LEDs operating at
greater than 200V. Other embodiments are possible using different
driver configurations or a boost supply at lower voltages.
[0038] The submounts 129 are arranged such that the LEDs 127 are
positioned surrounding the longitudinal axis of the lamp and emit
light generally toward the enclosure 112. The submounts 129 may
comprise a PCB, FR4 board, metal core printed circuit board (MCPCB)
or other similar structure. The submounts 129 may be made of a
thermally conductive material. In some embodiments the thickness of
the submounts may be about 1 mm-2.0 mm thick. For example the
thickness may be about 1.6 mm. In other embodiments a copper or
copper based lead frame may be used. Such a lead frame may have a
thickness of about 0.25-1.0 mm, for example, 0.25 mm or 0.5 mm. In
other embodiments, other dimensions including thicknesses are
possible. In some embodiments the submounts 129 may be
approximately 20 square mm. The entire area or substantially the
entire area of the submounts 129 may be thermally conductive such
that the submounts transfer heat to the heat sink 149. The
submounts 129 comprise a first LED mounting portion 151 that
functions to mechanically and electrically support the LEDs 127 and
a second connector portion 153 that functions to provide thermal,
mechanical and/or electrical connections to the heat sink 149 and
the electrical path. The submounts may include circuitry and may be
in the electrical path from the; lamp electronics to the LEDs. In
one embodiment CREE XLamp Starboards may be used as the submounts
129. The submounts 129 may include a mounting structure such as
receptacles 150 for receiving a fastener such as a screw that
engage threaded holes on the heat sink structures 151 for securing
the submounts 129 to the heat sink 149. In other embodiments other
fastening mechanisms may be used including thermal adhesive,
integrated mechanical mounting structures or the like.
[0039] In some embodiments, the LED lamp 100 is equivalent to a 100
Watt incandescent light bulb. Various embodiments of the LEDs
usable in an equivalent 100 Watt lamp are shown in the following
table:
TABLE-US-00001 Secondary Total Sim Fin Heat Power T i # Description
Version Sink? Orientation Component (W) (.degree. C.) 1
IPA_5_v3_mach_10- 5_v3- No Source Up XM-L2 x10 21 106.4 XML2
machinable 2 IPA_5_v3_mach_20- 5_v3- No Source Up XTE x20 21 102.7
XTE machinable 3 IPA_5_v3_mach_30- 5_v3- No Source Up XQD x30 21
102.8 XQD machinable 4 IPA_5_v4_mach- 5_v4-thin- No Source Up XM-L2
x10 21 110.6 1mm_10-XML2 1mm 5 IPA_5_v4_mach- 5_v4-thin- No Source
Up XM-L2 x10 21 105.1 2mm_10-XML2 2mm
[0040] For example, Sim #1 shows a lamp made with 10 XM-L2 LEDs
sold by CREE INC. using the large heat sink 149 shown in FIGS. 1-4.
No secondary heat sink is used. The LEDs are disposed in a facing
up orientation with a total power of 21 W and a junction
temperature of 106.4.degree. C. Sims #2 and #3 show the same
embodiment of the lamp using 20 CREE INC. XTE LEDs and 30 CREE INC.
XQD LEDs, respectively. Sims #4 and #5 show the results for an
embodiment of the lamp as shown in FIGS. 7-10 using 10 CREE INC.
XM-L2 LEDs where the heat sinks have the thin configuration shown
in FIGS. 8 and 10, rather than the relatively heavier and thicker
configuration of the heat sink of FIGS. 1-4, where Sim #4 has a 1
mm thick heat sink and Sim #5 has a 2 mm thick heat sink.
[0041] The base 102 comprises an electrically conductive Edison
screw 103 for connecting to an Edison socket and a housing portion
105 connected to the Edison screw. The Edison screw 103 may be
connected to the housing portion 105 by threads, adhesive,
mechanical connector, welding, separate fasteners or the like. The
housing portion 105 may comprise an electrically insulating
material such as plastic. Further, the material of the housing
portion 105 may comprise a thermally conductive material such that
the housing portion 105 may form part of the heat sink for
dissipating heat from the lamp 100. The housing portion 105 and the
Edison screw 103 define an internal cavity for receiving the
electronics 110 of the lamp including the power supply and/or
drivers or a portion of the electronics for the lamp. The lamp
electronics 110 are electrically coupled to the Edison screw 103
such that the electrical connection may be made from the Edison
screw 103 to the lamp electronics 110. The base 102 may be potted
to physically and electrically isolate and protect the lamp
electronics 110.
[0042] Referring to FIGS. 4 and 6, the housing 105 comprises a
first portion 105a that is connected to the Edison screw 103 and a
second portion 105b that extends into the LED assembly 130 and heat
sink 149 and that retain some or all of the lamp electronics 110. A
third portion 105c forms a support for supporting the LED assembly
130, heat sink 149 and enclosure 112 on the base 102. In one
embodiment the base 102 and lamp have a generally cylindrical shape
such that the support 105c is generally annular shape, however, the
housing 105 and support 105c may have other shapes. Support 105c
may be formed as a flange that extends from the base to form a
support surface 109 for the LED assembly 130, heat sink 149 and
enclosure 112. The housing 105 may have a diameter of approximately
21.5 mm and a length of approximately 60 mm.
[0043] Referring to FIG. 4, a support frame 111 is mounted on the
housing 105 and may be mounted on support 105c. The frame 111 may
be fixed to the support 105c by any suitable connection method such
as screws, adhesive, welding or the like. In one embodiment, the
frame 111 comprises a first annular connecting member 113 that is
supported on support 105c and a second annular connecting member
115 that supports the open end 112a of enclosure 112. The first
connecting member 113 and the second connecting member 115 are
connected to one another by a plurality of spacers 117 such that
the frame 111 has an open construction comprising openings between
the connecting members 113, 115 and spacers 117 that allow access
to the interior of the enclosure 112. The open end 112a of
enclosure 112 may be connected to the second connecting member 115
by any suitable connection method such as screws, adhesive, welding
or the like. While the housing 105, support 105c, member 113 and
member 115, are described as annular, these members may have other
shapes provided that they are able to adequately support enclosure
112 on base 102.
[0044] The heat sink 149 may be mounted on the connecting member
113 such that the heat sink comprises a LED mounting portion that
is disposed inside of enclosure 112 and a heat dissipating portion
that is at least partially disposed in the openings defined by
frame 111 such that the heat sink 149 is exposed to the exterior of
the lamp and may conduct heat from the LEDs 127 to the exterior of
the lamp. The heat sink 149 may comprise a plurality of separate
heat sink structures 151 that are mounted to the frame 111
independently of one another. As shown, the heat sink 149 comprises
a plurality of heat sink structures 151 each of which may support
at least one LED 127. In the illustrated embodiments the heat sink
structures 151 each support 2, 4 or 6 LEDs; however, each heat sink
structure may support no LEDs or may support one or more LEDs in
various combinations in addition to those shown in the figures. The
heat sink structures 151 extend from inside of the enclosure 112 to
the openings of frame 111 where they are exposed to the exterior of
the lamp to conduct heat away from the LEDs to the exterior of the
lamp. Because the heat sink structures 151 have a generally
rectilinear profile and are arranged in a circular or cylindrical
shape, passages 160 are formed between and behind the adjacent heat
sink structures 151 that allow air to circulate from the ambient
environment around the heat sink 149, submounts 129 and LEDs 127
and through the interior of the interior space of the heat sink.
Each heat sink structure 151 may comprise one or more mounting
surfaces 153 for mounting the submounts 129 such that the submounts
are thermally coupled to the heat sink structures 151 0f the heat
sink 149. The heat sink structures 151 also may comprise fin
structures 155 that are located in the openings of frame 111 for
dissipating heat to the ambient environment through the frame 111.
The fin structures increase the surface area of the heat sink
structures 151 to increase heat dissipation to the air. The fin
structures also create openings that communicate with the openings
in the frame 111 and that communicate with the interior space of
the heat sink such that air may flow from the ambient environment
through the heat sink. Heat is conducted from the LEDs 127 to the
submounts 129 and from the submounts 129 to the heat sink 149 where
the heat is dissipated to the ambient environment via the heat
sink. The mounting surfaces 153 may comprise flat planar areas for
receiving the submounts 129. The submounts 129 may be provided with
corner cut outs 160 or apertures as shown in FIG. 5 for receiving
screws or other fasteners for mounting the submounts 129 to the
heat sink structures 151. The submounts 129 may also be mounted to
the heat sink 149 using thermal epoxy, integrated mechanical
connectors and/or other connection mechanisms or a combination of
connection mechanisms. The enclosure 112 may be provided with an
opening 112b that allows air flow through the distal end of the
enclosure 112 through and around the heat sink 149 such that air
may flow along the length of the heat sink between the base 102 and
the distal end of the lamp.
[0045] The mounting surfaces 153 may be disposed on the heat sink
149 at a variety of angles relative to the longitudinal axis of the
lamp such that the LEDs 127 mounted on mounting surfaces 153 may
project light in any desired pattern such as an omnidirectional
lamp as shown. The mounting surfaces may be disposed in 360 degrees
about the longitudinal axis of the lamp such that a 360 degree
light pattern is generated. The mounting surfaces 153 may be
disposed at angles relative to the longitudinal axis of the lamp
other than 90 degrees to project light laterally, toward the base
102 and/or toward the distal end of the lamp. As shown in the
Figures each heat sink structure 151 comprises two mounting
surfaces 153. The mounting surfaces positioned closer to the distal
end of the lamp are disposed substantially parallel to the
longitudinal axis of the lamp such that the light from LEDs 127
mounted on this surface is projected primarily laterally. The
mounting surfaces positioned closer to the base of the lamp are
disposed at an angle relative to the longitudinal axis of the lamp,
between parallel and perpendicular, such that more of the light
from an LED mounted on this surface is projected toward the distal
end of the lamp. The angles of the mounting surfaces 153 may be
varied to vary the light pattern emitted from the lamp. Further,
while each heat sink structure 151 comprises two mounting surfaces
153 a greater or fewer number of mounting surfaces may be provided
on each heat sink structure. Each mounting surface may also support
more than one LED 127 and the types of LEDs supported on the
mounting surfaces may be different. The heat sink structures 151
may include mounting surfaces that are disposed radially beyond the
base 102 such that the base does not block light projected toward
the base.
[0046] In one embodiment the heat sink structures 151 have a
relatively thick construction where each heat sink structure is
relatively heavy and provides a relatively large heat sink as shown
in FIGS. 1-4. The heat sink structures may have a thickness of
approximately 3 mm, 4 mm, and/or 5 mm and may be in the range of
approximately 3-5 mm. Each heat sink structure 151 may have a
weight of approximately 20-35 grams. In one embodiment each heat
sink structure may have a weight of approximately 27.3 grams where
a heat sink 149 having five heat sink structures 151, as shown, has
a total weight of approximately 136.7 grams. The total weight of
the heat sink may be approximately 110-170 grams. In other
embodiments, the heat sink structures 151 may have a relatively
thin walled construction where the structures may be on the order
of approximately 1 mm thick (FIGS. 7 and 8) or approximately 2 mm
thick (FIGS. 9 and 10) and may be in the range of approximately 1-3
mm thick. Such heat sink structures may have a weight of about
approximately 3.8 grams for a 1 mm thick structure and a weight of
approximately 7.7 grams for a 2 mm thick structure, for a total
heat sink weight of 18.9 and 38.6 grams, respectively. Each heat
sink structure 151 may have a weight of approximately 3.8-10 grams.
The total weight of the heat sink with the thin heat sink
structures may be approximately 15-50 grams. While specific
embodiments of heat sink sizes and wall thicknesses are shown the
heat sink may have thicknesses and weights other than those shown
depending on the heat output by the LEDs and the thermal
requirements of the LEDs and/or lamp. The heat sink 149 may be made
of any suitable thermally conductive material or combination of
materials such as aluminum, ceramic or the like. The heatsink
structures 151 may be machined, cast, extruded or the like.
[0047] In one embodiment, a lamp constructed as described herein
using a 3-5 mm thick heat sink with ten CREE XML-2 LEDS for 21 W
total was shown to have a junction temperature of 106.4.degree. C.
In another embodiment a lamp constructed as described herein using
a 3-5 mm thick heat sink with twenty CREE XT-E LEDS for 21 W total
was shown to have a junction temperature of 102.7.degree. C. In
another embodiment a lamp constructed as described herein using a
3-5 mm thick heat sink with thirty CREE XQ-D LEDS for 21 W total
was shown to have a junction temperature of 102.8.degree. C. In yet
another embodiment a lamp constructed as described herein using a 1
mm thick heat sink with ten CREE XML-2 LEDS for 21 W total was
shown to have a junction temperature of 110.6.degree. C. In still
another embodiment a lamp constructed as described herein using a 2
mm thick heat sink with ten CREE XML-2 LEDS for 21 W total was
shown to have a junction temperature of 105.1.degree. C. In various
embodiments of the invention different numbers and types of LEDs
may be used. For example 15 CREE XP-G2 LEDS may be used, 20 CREE
XT-E LEDs may be used, 10 CREE XM-L2 LEDs may be used or 30 CREE
XQ-D LEDs may be used. The lamp has a total power of approximately
21 Watts and the junction temperature of the plurality of LEDs is
between approximately 105 and 111.degree. C.
[0048] FIG. 11 shows an embodiment of a submount 129 where the
submount is made of bendable substrate such as a metal core PCB
(MCPCB). Using such a submount the LEDs 127 may be mounted on the
submount 129 in a flat condition and the submount may be bent to
fit on the heat sink 149 such that rather than having a separate
submount on each mounting area 153 (as shown in the previous
figures) a single submount may be used that spans multiple mounting
areas 153. The submount may be folded or bent to locate the LEDs
127 on the mounting areas 153. One or more foldable submounts may
be used with one or more heat sink structures and in various
combinations. The MCPCB comprises a thermally and electrically
conductive core made of aluminum or other similar pliable metal
material. The core is covered by a dielectric material such as
polyimide. Metal core boards allow traces to be formed therein. In
one method, the core board is formed as a flat member and is bent
into a suitable shape. Because the core board is made of thin
bendable material and the anodes and cathodes may be positioned in
a wide variety of locations, and the number of LED packages may
vary, the metal core board may be configured such that it may be
bent into a wide variety of shapes and configurations. The LEDs 127
are located on the flat sections such that the core board may be
bent along the score lines to form the planar core board into a
variety of three-dimensional shapes where the shape is selected to
project a desired light pattern from the lamp 100. In one
embodiment the MCPCB is formed of five LED supporting areas
129a-129e each supporting at least on LED 127. The MCPCB may have a
central supporting area 129a from which four additional extension
supporting areas 129b-129e extend. The center supporting area 129a
may be formed as a rectangle where each of the four additional
supporting areas 129b-129e extend from one side of the rectangle.
The MCPCB may be bent such that the central supporting area 129a is
horizontal in the lamp (horizontal meaning transverse to the
longitudinal axis of the lamp) such that an LED 127 mounted on the
central supporting area 129a may project the majority of its light
out of the distal end of the enclosure 112. The four additional
supporting areas 129b-129e may be disposed at an angle relative to
the central supporting area such that the light from LEDs mounted
on these areas is projected primarily laterally. The different
supporting areas may be supported at a variety of angles to alter
the light pattern emitted from the light. While five mounting areas
are shown a greater or fewer number of mounting areas may be used
and may be arranged in patterns other than that shown in the
drawings. In another embodiment the central supporting area may be
a pentagon where five additional extension supporting areas extend
from the central supporting area. The MCPCB may be bent such that
the five extensions are disposed on the five heat sink structures
151 and the central supporting area spans the space between the
heat sink structures 151 and is disposed horizontally.
[0049] The LED assembly, whether made of a flexible submount such
as a flexible PCB submount, a bendable MCPCB submount, a lead frame
submount, a flex circuit, a hybrid combination of such submounts or
the like, may be formed to have the configurations shown and
described herein or other suitable three-dimensional geometric
shape. A "three-dimensional" LED assembly as used herein and as
shown in the drawings means an LED assembly where the submounts
comprise mounting surfaces for different ones of the LEDs that are
in different planes such that the LEDs mounted on those mounting
surfaces are also oriented in different planes. In some embodiments
the planes are arranged such that the LEDs are disposed over 360
degrees about the longitudinal axis of the lamp. Further when
individual submounts 129 are used as shown, for example, in FIGS.
1-5, individual submounts are also disposed in a three-dimensional
pattern
[0050] Connectors or conductors in the form of circuitry on the
substrates 129 such as traces connect to the anode and the cathode
pairs of the LEDs to provide the electrical path to the
anode/cathode pairs during operation of the LEDs. The submount 129
also comprises connector portion 153 that functions to couple the
LED assembly 130 to the heat sink 149 such that heat may be
dissipated from the LED assembly and to electrically couple the LED
assembly 130 to the electrical path. An LED or LED package
containing at least one LED 127 is secured to each anode and
cathode pair where the LED/LED package spans the anode and cathode.
The LEDs 127 may be attached to the submount by soldering.
[0051] In one embodiment of the lamp 100 the lamp has a lumen
output of approximately at least 1600 lumens in a steady state
operation where the LEDs reach an equilibrium temperature. The lamp
may have a color rendering index (CRI) of approximately at least 80
with a correlated color temperature (CCT) of less than
approximately 3000. The lamp 100 has an efficiency of at least
approximately 80 lumens per Watt (LPW). These operating parameters
are achieved without TIR optics. The operating parameters set forth
above are for one design of the lamp of the invention; however, the
lamp may be designed to meet other operating specifications for
different types of lamps.
[0052] With respect to the features described herein with various
example embodiments of a lamp, the features can be combined in
various ways. For example, the various methods of including
phosphor in the lamp can be combined and any of those methods can
be combined with the use of various types of LED arrangements such
as bare die vs. encapsulated or packaged LED devices. The
embodiments described herein are examples only, shown and described
to be illustrative of various design options for a lamp with an LED
array.
[0053] LEDs and/or LED packages used with an embodiment of the
invention and can include light emitting diode chips that emit hues
of light that, when mixed, are perceived in combination as white
light. Phosphors can be used as described to add yet other colors
of light by wavelength conversion. For example, blue or violet LEDs
can be used in the LED assembly of the lamp and the appropriate
phosphor can be in any of the ways mentioned above. LED devices can
be used with phosphorized coatings packaged locally with the LEDs
or with a phosphor coating the LED die as previously described. For
example, blue-shifted yellow (BSY) LED devices, which typically
include a local phosphor, can be used with a red phosphor on or in
the optically transmissive enclosure or inner envelope to create
substantially white light, or combined with red emitting LED
devices in the array to create substantially white light. Such
embodiments can produce light with a CRI of at least 80, at least
90, or at least 95. By use of the term substantially white light,
one could be referring to a chromacity diagram including a
blackbody 160 locus of points, where the point for the source falls
within four, six or ten MacAdam ellipses of any point in the
blackbody 160 locus of points.
[0054] A lighting system using the combination of BSY and red LED
devices referred to above to make substantially white light can be
referred to as a BSY plus red or "BSY+R" system. In such a system,
the LED devices used include LEDs operable to emit light of two
different colors. In one example embodiment, the LED devices
include a group of LEDs, wherein each LED, if and when illuminated,
emits light having dominant wavelength from 440 to 480 nm. The LED
devices include another group of LEDs, wherein each LED, if and
when illuminated, emits light having a dominant wavelength from 605
to 630 nm. A phosphor can be used that, when excited, emits light
having a dominant wavelength from 560 to 580 nm, so as to form a
blue-shifted-yellow light with light from the former LED devices.
In another example embodiment, one group of LEDs emits light having
a dominant wavelength of from 435 to 490 nm and the other group
emits light having a dominant wavelength of from 600 to 640 nm. The
phosphor, when excited, emits light having a dominant wavelength of
from 540 to 585 nm. A further detailed example of using groups of
LEDs emitting light of different wavelengths to produce
substantially while light can be found in issued U.S. Pat. No.
7,213,940, which is incorporated herein by reference.
[0055] Different embodiments of the LED assembly and heat sink are
possible. In various embodiments, the heat sink 149 may be
relatively shorter, longer, wider or thinner than that shown in the
illustrated embodiment. Moreover the LED assembly may engage the
heat sink 149 and lamp electronics 110 in a variety of manners. For
example, the heat sink may only comprise the heat dissipating
portions 155 and the LED mounting areas 153 may be integrated with
the LED assembly 130 such that the integrated heat sink mounting
areas and LED assembly engage the heat dissipating portion 155. In
some embodiments, the LED assembly and heat sink may be integrated
into a single piece or be multiple pieces other than as
specifically shown.
[0056] Once the LEDs 127 and submounts 129 are mounted on the heat
sink structures 151, the heat sink structures may be attached to
the base 102 and/or frame 111 such as by using screws, adhesive,
welding or the like. The enclosure 112 may be attached to the frame
111. In one embodiment, the LED assembly 130 and the heat sink 149
are inserted into the enclosure 112 through the neck 112a. The neck
112a and frame 111 are dimensioned and configured such that the rim
112a of the enclosure 112 sits on the upper support 115 of the
frame 111 with the heat dissipating portions 155 disposed at least
partially outside of the enclosure 112, in the open areas of frame
111. To secure these components together a bead of adhesive may be
applied to the upper support 115 of the frame 111. The rim of the
enclosure 112 may be brought into contact with the bead of adhesive
to secure the enclosure 112 to the frame 111 to complete the lamp
assembly.
[0057] In some embodiments the form factor of the lamp is
configured to fit within the existing standard for a lamp such as
the A19 ANSI standard. Moreover, in some embodiments the size,
shape and form of the LED lamp may be similar to the size, shape
and form of traditional incandescent bulbs. The LED lamp of the
invention is designed to provide desired performance
characteristics while having the size, shape and form of a
traditional incandescent bulb.
[0058] Although specific embodiments have been shown and described
herein, those of ordinary skill in the art appreciate that any
arrangement, which is calculated to achieve the same purpose, may
be substituted for the specific embodiments shown and that the
invention has other applications in other environments. This
application is intended to cover any adaptations or variations of
the present invention. The following claims are in no way intended
to limit the scope of the invention to the specific embodiments
described herein.
* * * * *